Epoxy tetramethylol methane and polymerization products thereof



Patented Feb. 15, 1949,

EPOXY TETRAMETHYLOL ME'EHANE AND POLYMERIZATION PRODUCTS THEREOF JosephA. Wyler, Allentown, Pa, assignor to Trojan Powder Company, acorporation of New York No Drawing. Application May 10, 1946, Serial No.668,774.

This invention relates to a composition of matter and method of makingit and more particularly to 1,3- (2,2 dimethyl propane monoxide and itsderivatives.

The application is a continuation in part of application Serial No.665,321 filed by me on April 26, 1946 and entitled Pentaerythritol-Condensation Products.

In this copending application there is described the condensation ofmolecules of pentaerythritol and certain derivatives of it by heatingwith mineral acids such as sulfuric and phosphoric acid. The copendingapplication is directed primarily to the making of complex compounds inwhich a plurality of molecules of the selected pentaerythritol compoundis condensed with the elimination of one less molecule of water thanthere are molecules of vthe pentaerythritol compound involved in thecondensation. Thus, two molecules of pentaerythritol itself on warmingwith a minor proportion of sulfuric acid gives polypentaerythritols;water being eliminated. There is disclosed in the copending applicationalso the formation of a compound of the formula:

did" CH CHzOH CHzOH This compound I call for convenience by the nameepoxytetramethylol methane, the compound being related topentaerythritol, which is tetramethylol methane, by the replacement oftwo hydroxy groups in ,a molecule by an oxygen atom, this replacementbeing accompanied by the loss of one molecule of water from a moleculeof the pentaerythritol. In a difierent system of nomenclature thecompound is 1,3-(2,2 dim'ethylol) propane monoxide.

The present invention is directed to this 1,3- (2,2 dimethylol) propanemonoxide and also to its reaction products, particularly withpentaerythritol, and their preparation and separation frompentaerythritol or the condensation products thereof such as one of thepolypentaerythritols.

Briefly stated, the invention comprises the compounds of the 1,3-(2,2dimethylol) propane monoxide class, of the general but not structuralformula 6 Claims. (61. 260-333) omonj QHiOH :c

in which a: is an integral number and ordinarily 1 to 'l inclusive. theherein described method of preparing such compounds which includesremoval of' water from pentaerythritol to give the monomer 1,3- (2,2dimethylol) propane monoxide and the separation of it, or its polymersformed on further warming, as by crystallization or by'crystallizationfollowed by differential settling rates of crys- .tals of the polymerand other compounds present material and unchanged pentaerythritol andpolypentaerythritol condensation products thereof, is then subjected totreatment to separate the epoxy material or its polymers from thepentaerythritol condensation products.

This treatment in the preferred method involves separationofalcohol-soluble materialby treatment with alcohol followed bydehydration and crystallization of the product. This alcohol and thebutanol recited in the following para graph are examples of loweraliphatic alcohols.

In another embodiment'the method includes concentrating an aqueoussolution of the product first formed by the acid treatment of thepentaerythritol compound, continuing the concentration almost to thepoint of crystallization, and then adding a volati'e liquid that is nota solvent for the epoxy compound, as, for example, butanol, distillingthe mixture, separating the condensate into an aqueous and non-aqueouslayer, and returning the non-aqueouslayer to the still untilsubstantially all the water is removed. There results a suspension ofcrystals of pentaerythritol, its condensation products and the epoxycompounds in the liquid. When boiling is discontinued, the crystals ofthe penta compounds settle rapidly whereas the crystals of the epoxycompounds settle slowly. The suspension The invention comprises also 3of the slowly settling epoxy compounds is .then decanted away from thecrystals of the penta compound. The crystals of the epoxy compounds soseparated may then be further purified by recrystallization as from hotwater.

Compounds made as described are considered to have the general structureshown in the following formula:

cmon onion onion Inc-demo omoxcmo CHLJ} om H.011 H.011 x onion in whichX=one' or any whole number. For the trimer X=l and for the pentamer X=3.For

and its polymers, particularly the trimer and the pentamer, are usefulespecially as bodying agents in the making of resins. Thus linseed oilfatty acids body rapidly with as little as 1% of any of the epoxycompounds to which reference has been made.

The invention will be further illustrated by detailed description inconnection with the following specific examples of the practice of it.

Exlmru 1 of trimer of 1,3-(2,2 dimethylol) propane monoxide Purepentaerythritol was heated with 0.2% of its weight of sulfuric acid withthe liberation of water, in accordance with the process disclosed in mysaid copending application, until the OH content of the product wasabout 37%. More specifically the pentaerythritol and sulfuric acidmixture was heated at a temperature of 220 to 235 C. for a few minutesand the heating discontinued when a sample removed and tested bystandard methods shows hydroxyl content of 37%. The contents were thendischarged intoa cooling pan.

100 parts of this product were refluxed with 400 parts of ordinarycommercial ethyl alcohol for about 2 hours and the hot mixture filtered.The filtrate was evaporated to dryness on the steam bath, taken up inhot water, decolorlzed by means of charcoal, filtered, and this filtrateplaced in a suitable still and evaporated to small volume. r 1

Just before any crystals are caused to separate during the evaporation,normal butyl alcohol is added in a steady stream in order to effect anazeotropic distillation, to dehydrate the mixture and to cause theseparation of clean-cut crystals. By this procedure coarse crystals ofpure pentaerythritol (unconverted in the original heating process) andfine crystals of the trimer of 1,3-(2,2 dimethylol) propane monoxideseparate. The latter crystals are readily separated by decantation fromthe denser crystals of pentaerythritol, as by stirring the whole mixtureand Preparation 4 pouring oil the suspended crystals as soon as thelarger crystals have settled.

50 parts of this fine material were dissolved in 200 parts of hot water,the mixture cooled to room temperature and the crystals'which formfiltered ofl, washed and dried.

The trimer, 1,3-(2,2 dimethylol) propane monoxide, is a whitepulverulent, crystalline product of M. P. about 208 C., somewhat solublein ethyl alcohol, but less soluble in butyl alcohol, slightly soluble incold water but more soluble in hot. It is more soluble inwatercontaining some pentaerythritol than it isin pure water and appearsto become somewhat hydroxylated upon prolonged heating in water. It issoluble in hot diethylene glycol and may be precipitated therefrom bymeans of ethyl alcohol or cold water.

Its formula may be written:

Preparation of the pentamer 0 1,3-(2,2 dimethylol) propane monoxide Purepentaerythritol was heated with 0.2% of its weight of sulfuric acid,with the liberation of water, in accordance with the process describedin Example 1, to obtain a conversion product containing 38.05% OH. Onepart of this product was mixed with 14 parts of water and the mixtureboiled for about one half hour. The hot C.+) mixture was filtered awayfrom undissolved material and the clear filtrate allowed to cool to roomtemperature. The flocculent precipitate which formed was filtered off,washed with water, dried and pulverized.

This pulverized product melted at about 230.5 C. and contained 29.69%OH, by acetyl method of analysis which, it should be said, gives onlyapproximate percentages. It was again boiled up in water (3 times itsweight of water) and filtered at 70 C. The material filtered off was 81%of the weight of the impure product started with and now melted at233.5-234.5 C. A second such treatment did not alter the melting pointof the product which was a white, pulverulent, lowdensity material,diflicultly soluble in water, although slightly'more soluble in the butthan in the cold; insoluble in anhydrous alcohol; soluble in hotdiethylene glycol, from which it may be precipitated by means of ethylalcohol; rather difiicultly soluble in glycol or glycerine and insolublein ether.

The purified product contains no ketonic or aldehydic groups and wasfound to be the pentamer of the general but not structural formula CHzOHonion 5 which by nitration contains 28.79% OH. For such compound themolecular weight should be 590.65. By nitrating the compound to thedecanitrate, dissolving the decanitrate in trinitrotoluene, measuringthe depression of the freezing point of the T. N. T. by a known weightof the decanitrate, and calculating the molecular weight of thepentamer, the molecular weight was found to be within 3.5% of thetheory, an agreement Exmtn 3 Preparation of the heptamer of 1,3-(2,2dimethulol) propane monoxide Pure pentaerythritol was heated with 0.2%of its weight of sulfuric acid, with the liberation of water, inaccordance with the process disclosed in my said copending applicationand as described in Example 1 above, to obtain a conversion product of Hcontent about 30%, say 28% to 32%.

One part of this product was mixed with 14 parts of Water and themixture boiled for about one-half hour. The hot (90 C.+) mixture wasfiltered and the residue repeatedly treated with boiling water andfiltered at a temperature above 90 0., until a test of the clearfiltrate indicated practically no hot water soluble material left in theresidue. This repeated boiling in water removes the lower polymers whichare relatively more soluble than the higher which are practicallyinsoluble in water but soluble in hot glycerine or diethyleneglycol fromwhich they may be precipitated by means of ethyl alcohol, methylalcohol, or water. I

In the present example, in which a 30% OH conversion product wasinitially used, the final insoluble fraction obtained above was found tobe the heptamer, that is,

'OHgOH CHzOH CHZOH (Hg.1.CHz.O{.CHz.$.CHz-O ,CHa CH HzOH 310B 5 H1013This product is then dried.

I value, otherwise the yields of the heptamer are too low or theheptamer present is dificult to separate from the lower polymers,especially from the pentamer.

Although, in the examples given, I have used a pentaerythritolconversion product made with the invention herein chosen for the purposeof illustration which do not constitute departures from the spirit andscope oi the invention.

What I claim is: t

1. A 1,3-(2,2 dimethylol) propane monoxide compound of the generalformula onion onion x in which X represents an odd integral numberwithin the range 1 to 7 inclusive.

2. The method of making a compound of the kind described in claim 1which comprises heating pentaerythritol with a small proportion of amineral acid, to cause condensation of 'molecules of pentaerythritolwith loss of water and decrease of hydroxy content of the remainingproduct, refluxing theproduct with a lower aliphatic alcohol solvent,and then crystallizing the material from hot water.

3. The method of making a compound oi'the kind described in claim 1which comprises heating pentaerythritol with a small proportion of amineral acid, to cause condensation of molecules of pentaerythritol withloss of water and decrease of hydroxy content of the remaining prodnot,to form a wet composition including the 1,3-(2,2 dimethylol) propanemonoxide compound of the kind described in claim 1 and unchangedpentaerythritol, suspending the said composition in butanol, warming anddistilling the mixture until practically all water is removed from themixture, adding any additional butanol required to keep the saidcomposition suspended in the butanol, allowing the suspension to settleuntil coarse crystals therein have settled, and then decanting oil thesupernatant liquor and 1,3-(2,2 dimethylol) propane monoxide compoundsuspended therein, the coarse crystals separated by settling containingmost of the unchanged pentaerythritol.

4.1m making the heptamer of 1,3; -(2,2 dimethyiol) propane monoxide, themethod which comprises heatingpentaerythritol with a minor proportion ofan acid serving as a dehydration catalyst until the content of hydroxygroups is H2SO4,'I do not confine myself solely to this par.-

ticular type of product. I may use a product made from phosphoric acidin any of its forms which are eflective in splitting 01? water frompentaerythritol as described in my said copending application, or I mayuse a pentaerythritol prodnot made from any other agent capable ofremoving water from pentaerythritol in essentially the same manner.Although the productsused in the examplesv contained about 37% of OH Ido not confine myself to this or any other specific QH' content. I mayuse a product containing as low as about 26% OH, although I prefer onecontaining about 34% OH. If the OH content is too low, the separationsbecome more diflicult. If the -OH content is too high, the yieldsobtained are too low.

It will be understood that it is intended to cover all changes andmodifications oi the examples of reduced'to about 30%, repeatedlyextracting the product with hot water to remove lower polymers of the1,3-(2,2 dimethylol) propane monoxide,

and then drying theheptamer which remains undissolved.

5. 1,3-(2,2 dimethylol) propane monoxide. 6. The trimer of 1,3-(2,2dimethylol) propane monoxide.

JOSWE A. warm.

nmaucns CITED The following references are of record in the file of thispatent:

UNITED STATES PATmTS 2,4013%!) Burghardt et a1. June 11, 1945Certificate of Correction Patent No. 2,462,048. February 15, 1949.

JOSEPH A. WYLER It is hereby certified that errors appear in the printedspecification of the above numbered patent requiring correction asfollows:

Column 1, line 3, for dimethyl read dimethylol; column 4, line 42, for-29.69% read 29.62%;

and that the said Letters Patent should be read with these correctionstherein that the same may conform to the record of the case 1n thePatent Oflice.

Signed and sealed this 28th day of Jnne, A. D. 1949.

THOMAS F. MURPHY,

Assistant Oommiuioner of Patents.

